This invention pertains to fabric filter bag constructions used in baghouses for controlling air pollution and more particularly to a means for capping damaged filter bag units suspended within the baghouse while in use.
Particulate matter such as dirt or fly ash can be removed from air streams by passing the contaminated air stream into a baghouse and through a series of fabric filter cylindrical bags comprising an elongated tubular shaped fabric bag telescoped over a cylindrical open wire cage. In reverse jet baghouse operations, the contaminated air flow is periodically interrupted while a jet of reversed forced air is applied to the interior of the fabric filter cylinder bag to dislodge particulate matter collected on the exterior surfaces of the filter bags. A venturi nozzle is located above each filter bag and adapted to provide high velocity air releases in short pulses in response to an automatically controlled source of compressed air. To facilitate the direction of the pulsed air within each filter bag, a venturi is interconnected within the top portion of each filter bag unit.
Problems are often encountered with fabric filter bag assemblies where individual filter bag units or cylinders become damaged in use and typically sustain tears or ribs in the fabric filters, which permits unfiltered air to pass through the baghouse. Damaged filter bag units must be individually removed and replaced with a new filter bag unit to maintain the effectiveness of the baghouse filtering system containing a plurality of individual filter bag units. Removing defective filter bag units, however, is a very time consuming operation particularly since the bolts securing the units to an overhead suspending mechanism are often corroded. The corroded bolts and studs often require a torch and welder to remove the same, which causes a costly and time consuming repair operation. Thus, a tear or hole in a single filter bag unit requires a lengthy shut-down of the entire baghouse to merely remove a defective filter bag unit.
It now has been found that a simple and easy means for capping a defective filter bag unit can be installed quickly in a damaged unit without removing the defective unit from the baghouse. The capped filter bag unit effectively prevents unfiltered air from passing through the damaged unit and forces the unfiltered air through the remaining functioning filter bag units. In accordance with this invention, the capping means comprises a toggle locking mechanism adapted to cover the venturi opening in the defective unit to block air from entering the unit whereby the capped damaged unit can remain in the baghouse without harming the baghouse air filtration. In accordance with this invention, the capping means for the venturi comprises a toggle mechanism having a threaded rod adapted to provide locking engagement of an upper flat plate with the upper peripheral flat collar surface of the venturi and a lower elongated wobble locking plate adapted to slip through the lower contracting throat of the venturi and provide locking engagement with the lower end of the venturi. By tightening the locking bolt on the threaded rod the upper plate effectively caps the venturi while the opposite ends of the lower wobble plate overlie opposite ends of the lowermost edges of the venturi locking with the bottom of the venturi to provide secure locking engagement of the capping means for the venturi. Hence, the capped fabric filter bag can be retained attached to the tube sheet within the baghouse until the entire system of filter bags is removed for repair. These and other advantages of this invention will become more apparent by referring to the drawings and the detailed description of the invention.